High performance or wavelength configurable detector

Abstract

A detector. The detector includes a first collector, a first interface layer on the first collector, a first absorber on the first interface layer, a second interface layer on the first absorber, and a second collector on the second interface layer. The first absorber is configured to absorb photons to generate electron-hole pairs. The first interface layer may include a barrier configured to impede the flow of majority carriers from the first absorber to the first collector. The second barrier may include a barrier configured to impede the flow of majority carriers from the first absorber, or from a second absorber, to the second collector.

What is claimed is: 
     
       1. A detector comprising:
 a first collector; 
 a first interface layer, on the first collector; 
 an absorber, on the first interface layer; 
 a second interface layer, on the absorber; and 
 a second collector, on the second interface layer, 
 the absorber being configured to absorb photons, 
 the detector being configured such that both the first collector and the second collector concurrently collect minority carriers generated in the absorber. 
 
     
     
       2. The detector of  claim 1 , wherein:
 the first interface layer comprises:
 a barrier configured to block the flow of majority carriers from the absorber to the first collector; or 
 a p-n heterojunction; or 
 a p-n homojunction, and 
 
 the second interface layer comprises:
 a barrier configured to block the flow of majority carriers from the absorber to the second collector; or 
 a p-n heterojunction; or 
 a p-n homojunction. 
 
 
     
     
       3. The detector of  claim 1 , comprising, as a major component, a III-V semiconductor, a II-VI semiconductor, or a group IV semiconductor. 
     
     
       4. The detector of  claim 1 , wherein the absorber comprises, as a major component, InAlSb alloy or InAsSb alloy or AlInAsSb alloy. 
     
     
       5. The detector of  claim 1 , wherein the absorber comprises a structure selected from the group consisting of InAs/InAsSb superlattices, InAs/GaSb superlattices, InAs/GaInSb superlattices, InAs/GaSb/AlSb superlattices, and combinations thereof. 
     
     
       6. The detector of  claim 1 , wherein the absorber comprises, as a major component, an n-type semiconductor or a p-type semiconductor. 
     
     
       7. The detector of  claim 1 , wherein the absorber has a uniform composition. 
     
     
       8. The detector of  claim 1 , wherein the absorber has a graded composition and a bandgap of the absorber is:
 wider in a first region of the absorber, and 
 narrower, than in the first region, in:
 a second region between the first region and the first interface layer, and 
 a third region between the first region and the second interface layer. 
 
 
     
     
       9. The detector of  claim 1 , wherein the absorber has a linearly graded composition. 
     
     
       10. The detector of  claim 1 , wherein the absorber has a step-graded composition. 
     
     
       11. The detector of  claim 1 , further comprising a metal contact penetrating, and electrically isolated from:
 the second interface layer, and 
 the second collector, and 
 electrically connected to the absorber. 
 
     
     
       12. The detector of  claim 1 , further comprising:
 a metal grid contact on the second collector, 
 the metal grid contact being electrically connected to the second collector and to the first collector. 
 
     
     
       13. The detector of  claim 1 , further comprising an array common layer on the first collector. 
     
     
       14. The detector of  claim 1 , further comprising:
 a metal grid contact on the second collector and electrically connected to the second collector; and 
 an array common layer on the first collector, 
 wherein the metal grid contact is electrically connected to the array common layer. 
 
     
     
       15. An array detector, comprising a plurality of pixels each comprising the detector of  claim 1 , the pixels being separated by a plurality of trenches extending at least through the second collector, through the first interface layer, and through all intervening layers between the second collector, and the first interface layer. 
     
     
       16. The detector of  claim 1 , further comprising a metal contact penetrating, and electrically isolated from:
 the second interface layer, and 
 the second collector, and 
 electrically connected to the absorber. 
 
     
     
       17. The detector of  claim 1 , having a recess extending through:
 the first collector, 
 the first interface layer, 
 the absorber, 
 the second interface layer, and 
 the second collector, 
 the detector further comprising an insulating layer on an interior surface of the recess, and a planarization fill in an interior volume of the insulating layer. 
 
     
     
       18. A detector comprising:
 a first collector; 
 a first interface layer, on the first collector; 
 a first absorber, on the first interface layer; 
 a minority carrier cross talk prevention barrier on the first absorber; 
 a second absorber on the minority carrier cross talk prevention barrier; 
 a second interface layer, on the second absorber; and 
 a second collector, on the second interface layer, 
 each of the first absorber and the second absorber being configured to absorb photons, 
 wherein:
 the first absorber comprises, as a major component, an n-type semiconductor or a p-type semiconductor, 
 the second absorber comprises, as a major component, an n-type semiconductor or a p-type semiconductor, 
 the second absorber has a smaller bandgap than the first absorber, and 
 the first interface layer is a first barrier layer configured, by selection of:
 a thickness of the first barrier layer, and 
 a doping level of the first barrier layer, 
 
 to enable the flow of minority carriers from the first absorber to the first collector upon the application of a first bias to the detector to enable tunneling of minority carriers through a barrier. 
 
 
     
     
       19. The detector of  claim 18  further comprising a metal contact penetrating, and electrically isolated from:
 the second interface layer, and 
 the second collector, and 
 electrically connected to the second absorber. 
 
     
     
       20. The detector of  claim 18 , wherein the second interface layer forms a second energy barrier configured to impede the flow of minority carriers from the second absorber to the second collector in the absence of a bias, and to enable the flow of minority carriers from the second absorber to the second collector upon the application of a second bias to the detector. 
     
     
       21. The detector of  claim 18  wherein the second interface layer is a second barrier layer configured by selection of:
 a thickness of the second barrier layer, and 
 a doping level of the second barrier layer, 
 to enable the flow of minority carriers from the second absorber to the second collector upon the application of a second bias to the detector. 
 
     
     
       22. The detector of  claim 21 , wherein the magnitude of the first bias is larger than the magnitude of the second bias. 
     
     
       23. The detector of  claim 22 , wherein the magnitude of the second bias is between 10 mV and 200 mV. 
     
     
       24. The detector of  claim 22  configured:
 to collect minority carriers from only the second absorber when a bias having a magnitude greater than the magnitude of the second bias and less than the magnitude of the first bias is applied to the detector, and 
 to collect minority carriers, concurrently from the first absorber and from the second absorber, when a bias with a magnitude greater than the magnitude of the first bias is applied to the detector. 
 
     
     
       25. The detector of  claim 21 , wherein the magnitude of the first bias is smaller than the magnitude of the second bias. 
     
     
       26. The detector of  claim 25 , wherein the magnitude of the first bias is between 10 mV and 200 mV. 
     
     
       27. The detector of  claim 25  wherein the detector is configured:
 to collect minority carriers from only the first absorber when a bias having a magnitude greater than the magnitude of the first bias and less than the magnitude of the second bias is applied to the detector, and 
 to collect minority carriers, concurrently from the first absorber and from the second absorber, when a bias with a magnitude greater than the magnitude of the second bias is applied to the detector. 
 
     
     
       28. An array detector, comprising a plurality of pixels each comprising the detector of  claim 25 , the pixels being separated by a plurality of trenches extending at least through the second collector, through the first interface layer, and through all intervening layers between the second collector, and the first interface layer. 
     
     
       29. The detector of  claim 18 , having a recess extending through:
 the first collector, 
 the first interface layer, 
 the first absorber, 
 the minority carrier cross talk prevention barrier, 
 the second absorber, 
 the second interface layer, and 
 the second collector, 
 the detector further comprising an insulating layer on an interior surface of the recess, and a planarization fill in an interior volume of the insulating layer. 
 
     
     
       30. A method of forming a detector, the method comprising:
 forming a first collector; 
 forming a first interface layer on the first collector; 
 forming a first absorber on the first interface layer; 
 forming a second interface layer on the first absorber; and 
 forming a second collector on the second interface layer, 
 the first absorber being configured to absorb photons, 
 wherein the first absorber has a graded composition and a bandgap of the first absorber is:
 wider in a first region of the first absorber, and 
 narrower, than in the first region, in:
 a second region between the first region and the first interface layer, and 
 a third region between the first region and the second interface layer. 
 
 
 
     
     
       31. The method of  claim 30 , wherein:
 the first interface layer comprises:
 a barrier configured to impede the flow of majority carriers from the first absorber to the first collector; or 
 a p-n heterojunction; or 
 a p-n homojunction, and 
 
 the second interface layer comprises:
 a barrier configured to impede the flow of majority carriers from the first absorber to the first collector; or 
 a p-n heterojunction; or 
 a p-n homojunction. 
 
 
     
     
       32. A method of operating a detector,
 the detector comprising:
 a first collector; 
 a first interface layer, on the first collector; 
 a first absorber, on the first interface layer; 
 a minority carrier cross talk prevention barrier on the first absorber; 
 a second absorber on the minority carrier cross talk prevention barrier; 
 a second interface layer, on the second absorber; 
 a second collector, on the second interface layer; and 
 a metal contact penetrating, and electrically isolated from, the second interface layer and the second collector, 
 wherein:
 the second absorber has a smaller bandgap than the first absorber, 
 the first interface layer is a first barrier layer configured, by selection of:
 a thickness of the first barrier layer, and 
 a doping level of the first barrier layer, 
 
 to enable the flow of minority carriers from the first absorber to the first collector upon the application of a first bias to the detector to enable tunneling of minority carriers through a barrier, 
 
 
 the method comprising:
 absorbing, via the first absorber, photons; 
 enabling the flow of minority carriers, by tunneling through a barrier, from the first absorber to the first collector; and 
 enabling the flow of minority carriers from the second absorber to the second collector.